Journal of Volcanology and Seismology最新文献

{"title":"Epithermal Ag–Au Mineralization in the Kyplatap Volcanic Field, Central Chukotka","authors":"A. G. Pilitsyn,&nbsp;A. V. Volkov,&nbsp;N. E. Savva,&nbsp;A. V. Grigorieva,&nbsp;T. A. Pilitsyna,&nbsp;N. V. Sidorova","doi":"10.1134/S0742046322060057","DOIUrl":"10.1134/S0742046322060057","url":null,"abstract":"<p>This paper discusses mineralogic and geochemical features of dominantly silver mineralization in secondary quartzites of the Kyplatap volcanic field (KVF) confined to the southeastern flank of the eponymous intrusive dome structure (IDS) that complicates the Palyavaam–Pykarvaam volcano-tectonic depression which is part of the Chaun zone of the Central Chukchi sector of the Okhotsk–Chukchi volcanogenic belt (OChVB). The Kyplatap IDS was formed as a large laccolite-like subvolcanic body intruded into the Alkakvun rhyolites and trachyrhyolites. The KVF contains an abundance of secondary quartzites that compose both linear zones along faults mostly northeast striking and fault-bounded isometric fields. Potential ore bodies are represented by linear zones of crushed and brecciated secondary quartzites accompanied by quartz veinlets and veins. The ore bodies are long up to 200 m and 2–5 m thick. Spotty, veinlet-impregnated, and brecciated structures predominate in the ore bodies. The ore mineralization is mostly impregnated, less frequently in veinlets. The main vein minerals are quartz (30–70%), hydromica (15–20%), sericite, kaolinite, adularia, ferrous carbonate, zircon, chlorite, and alunite. The main ore minerals are pyrite, arsenopyrite, acanthite, polybasite, pearceite, and native silver. The typomorphic feature of the mineralization is thin intergrowths of silver sulfosalts, native silver, and iron hydroxides. We note that dominantly silver mineralization in secondary quartzites within the OChVB was found for the first time ever. The results of surveys classify the Kyplatap ore occurrence as a gold-silver mineral type deposit (Au/Ag = 1 : 450 on average) of the selenium subtype because of considerable admixture of selenium in the ore minerals. The occurrence of Ag mineralization in secondary quartzites and mudstones may provide evidence that it belongs to the high-sulfidation epithermal class. These features of the KVF epithermal mineralization are largely similar to the formation of siliceous and quartz–alunite lithocaps that are formed above degassing intrusions. In such conditions, the HS-type ore-bearing fluids are either not formed in the system or did not reach the epithermal depths. The ore field is poorly or moderately eroded, what is indicated by a practically complete absence of minerals of the polymetallic association and by the dominance of acanthite and silver sulfosalts over native phases.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"397 - 408"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4644299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of Fracture in a Granite Specimen Using Observations of Acoustic Emission","authors":"V. T. Belikov,&nbsp;I. A. Kozlova,&nbsp;D. G. Ryvkin,&nbsp;A. K. Yurkov","doi":"10.1134/S0742046322030010","DOIUrl":"10.1134/S0742046322030010","url":null,"abstract":"<p>Experimental data were interpreted using two amplitude–frequency spectra of acoustic emission as recorded during the application of a uniaxial load to a granite specimen until it fractured. The interpretation procedure was based on the model of disk-shaped cracks. The results enabled us to analyze the variation in structural parameters in the specimen, as well as the fracture process during intervals between the times when the spectra were recorded.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"377 - 384"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4510757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Vp/Vs Kinematic Parameter in the Southern Segment of the Kamchatka Seismic Subduction Zone during the Precursory Period of the March 25, 2020, MW = 7.5 Earthquake and Its Aftershock Process","authors":"M. S. Kuchai,&nbsp;L. B. Slavina","doi":"10.1134/S0742046322050062","DOIUrl":"10.1134/S0742046322050062","url":null,"abstract":"<p>The Vp/Vs kinematic parameter for the Kamchatka seismic subduction zone has been long monitored on a regular basis. This has allowed estimating the behavior of the parameter and revealing its features during the precursory period and actual rupturing of the March 25, 2020 earthquake which occurred in the Pacific plate at the contact between the Pacific plate and the continental slope of Kamchatka. The March 25, 2020 earthquake with its high magnitude (<i>M</i>_L = 7.6, <i>M</i>_W = 7.5) is a rare enough event to occur in the Pacific plate. Knowledge of earth structure in the source region of the earthquake was updated based on the results of deep seismic sounding and continuous seismic profiling which was carried out in the area in the past. It was shown that the earthquake source area is at an inflection in the descending Pacific plate. The source area lies in the layer at the boundary between the asthenosphere and the crust and mantle. The layer is at depths of 30‒60 km and has lower Vp and Vs velocities. The inflection region along Kamchatka shows lower Vp/Vs values, which is a sign of extension along the plate. The source area is in the contact between the Pacific plate, which is subducting under the southern end of Kamchatka, and the North Kuril Islands, as well as the Sea-of-Okhotsk plate. The region shows a distinct change in the anomalous values of the parameter from lower to higher, with the latter being typical for compression. Our study has allowed estimating possible regions of tension and compression in the geological medium.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"365 - 376"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4514706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral Analysis of Large Earthquakes in the Baikal–Mongolia Region As Recorded at Irkutsk and Ulaanbaatar in 2020–2021","authors":"V. I. Dzhurik,&nbsp;E. V. Bryzhak,&nbsp;Ts. Batsaikhan,&nbsp;S. P. Serebrennikov,&nbsp;A. N. Shagun,&nbsp;A. Yu. Eskin","doi":"10.1134/S0742046322050049","DOIUrl":"10.1134/S0742046322050049","url":null,"abstract":"<p>We present an analysis of spectral content for three large earthquakes which occurred in the Baikal–Mongolia region, for hard soils in Irkutsk and Ulaanbaatar cities. The earthquakes were recorded from the same seismic source zones (SSZ) in 2020 and in 2021. We used accelerograms, frequency characteristics of upper soil layers, and ground motion spectra to describe and analyze the behavior of the earth at recording sites. We estimated variations in the spectral content of the large earthquakes, and their records were used to set up a common basic signal with due account of the SSZ for soils of the first category in Irkutsk and Ulaanbaatar. The results of this analysis provide the basis for future prediction of seismic effects due to large earthquakes in the Baikal–Mongolia region.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"385 - 395"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4514712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultra Acid Sulfate Chloride Waters of Baransky Volcano on Iturup Island, Kurils. The Composition and Output of Magmatic and Rock-Forming Components","authors":"E. G. Kalacheva,&nbsp;Yu. A. Taran,&nbsp;T. A. Kotenko,&nbsp;E. V. Voloshina,&nbsp;D. M. Erdnieva","doi":"10.1134/S0742046322050050","DOIUrl":"10.1134/S0742046322050050","url":null,"abstract":"<p>We have obtained new data on the chemical composition (including trace elements) and discharge of the Golubye Ozera ultra acid boiling springs which emit water on the southwestern slope of Baransky Volcano, Iturup Island. It is shown that the cation composition corresponds to solution of 1 g host rock and 1 L water. We carried out hydrologic and hydrochemical measurements to find the total hydrothermal release of magmatic volatiles Сl and S (in the form SO₄) along the beds of the main streams that drain the solfataric fields and springs of Baransky Volcano (Kipyashchy Creek and Sernaya River) and estimated the chemical erosion affecting the volcanic edifice. The total measured hydrothermal discharge of Cl and SO₄ into the Pacific Ocean reaches 14 t/d and 41 t/d, respectively. The mixed chemical erosion affecting the volcanic deposits in the Sernaya R. basin is about 150 t/km²/yr. The contribution of Kipyashchy Creek into the discharge of dissolved rock-forming components is above 30% of total discharge into the Pacific Ocean on the part of the Sernaya River.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"349 - 364"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4811390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Geochemical Features of Au-Ag Epithermal Mineralization at the Kayenmyvaam Volcanic Uplift, Central Chukotka","authors":"A. V. Volkov,&nbsp;A. A. Volfson,&nbsp;A. L. Galyamov,&nbsp;K. Yu. Murashov","doi":"10.1134/S0742046322050086","DOIUrl":"10.1134/S0742046322050086","url":null,"abstract":"<p>This paper considers geochemical features of the Au-Ag epithermal mineralization at the Kayenmyvaam volcanic uplift (KVU) situated in the middle of the Chukchi segment which is part of the inner zone of the Okhotsk–Chukchi volcanogenic belt (OChVB). New evidence is presented concerning the composition and concentrations of trace elements, including REEs, in the ores of Au-Ag deposits (Arykevaam, Kyaenmyvaam, and Televeem). The ores were found to be enriched in a wide range of trace elements (Li, Se, Mo, Au, Ag, As, Sb, Cu, Pb, In, Cd, Tl, Zn, Bi, Te, and W). The enrichment ratios vary between a few times (Li, Se, Bi, Zn, Tl, In) to tens (Mo, Te, Pb, Cd), hundreds (As, Cu), thousands and tens of thousand times (Au, Ag, Sb). Comparative analysis of the distribution patterns of trace elements shows synchronous enrichment of the ores in similar sets of trace elements. The ores were found to be dominated by light “hydrophile” lanthanoids of the “cerium” group, slightly inclined near-chondrite patterns, without obvious europium maxima and minima, which have configurations similar to the REE patterns of volcanic rock sequences of the andesite–diorite series. The ore-forming fluids belonged to an NaCl–H₂O hydrothermal system enriched in Cl relative to F; the Y/Ho ratios in the ores correspond with the range of ratios characteristic for present-day hydrothermal fluids in the backarc basins. The low Co/Ni ratios in the ores probably reflect a large involvement of meteoric near-surface fluids in the mineralization. The Ce/Ce* and Eu/Eu* ratios vary between slightly negative to moderately positive values (Ce/Ce* between 0.71 and 1.07) and (Eu/Eu* between 0.63 and 1.14). This combination of Ce/Ce* and Eu/Eu* corresponds to oxidizing conditions that were existent during the mineralization. The geochemical data indicate andesitic magmas and meteoric waters as the most likely sources of the fluids. The results classify the mineralization under study as belonging to the high sulfidation epithermal class.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"323 - 333"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4515845","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Upper Kedon Area of Intraplate Cenozoic Alkaline Basaltoids, Northeast Russia","authors":"V. V. Akinin,&nbsp;E. A. Brusnitsyna,&nbsp;V. M. Kuznetsov,&nbsp;V. V. Leonova,&nbsp;S. D. Shvedov","doi":"10.1134/S0742046322050025","DOIUrl":"10.1134/S0742046322050025","url":null,"abstract":"<p>This study is concerned with the structure and composition of a sheet of Cenozoic alkaline basaltoids (basanites and trachybasalts) in the upper reaches of the Kedon River, in the Kedon Uplift of the Omolon Massif. Mineralogical and geochemical data provide evidence of an intraplate, poorly differentiated type of magmas. Geochronologic isotope data (⁴⁰Ar/³⁹Ar and K-Ar methods) indicate a Late Miocene age for the eruptions in the time span between 9 and 7 ± 1 Ma. The magma source contained a considerable percentage of pyroxenites and, judging from the isotopic composition of Sr, Nd, and Pb volcanics, it is similar to the PREMA mantle component that is also characteristic for other Cenozoic alkaline basalt occurrences in Northeast Asia. The potential temperature of the mantle beneath the volcanic area is similar, judging from theoretical calculations, to the mean value of an unexcited mantle, and is consistent with the scenario of lithospheric extension initiated by remote tectonic events.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"334 - 348"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4514720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fundamental Achievements of Academic Science in Studies of Volcanoes and Earthquakes in Kamchatka","authors":"E. I. Gordeev,&nbsp;G. A. Karpov","doi":"10.1134/S0742046322040042","DOIUrl":"10.1134/S0742046322040042","url":null,"abstract":"<p>This paper reviews the results of fundamental importance achieved by the Institute of Volcanology and Seismology (IV&amp;S), Far East Branch (FEB), Russian Academy of Sciences (RAS) for the period 1962‒2021. We consider the most important achievements classified under the following headings: <i>Volcanological research</i> includes petrologic and geochemical features of ejecta by volcanoes in the Kuril–Kamchatka region; the age of volcanoes and the phases of volcanogenic catastrophism in Kamchatka; hydrothermal systems and geothermal reserves of Kamchatka; hydrothermal metasomatism and volcanogenic mineral generation and mineralization; <i>Geophysical research</i> includes the seismology of volcanoes; deformation at active volcanoes; tectonic earthquakes and tsunamis; the internal structure of volcanic systems.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 4","pages":"239 - 250"},"PeriodicalIF":0.7,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4565155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wave-Related, Electrical, and Magnetic Effects Due to the January 15, 2022 Catastrophic Eruption of Hunga Tonga–Hunga Ha’apai Volcano","authors":"V. V. Adushkin,&nbsp;Yu. S. Rybnov,&nbsp;A. A. Spivak","doi":"10.1134/S0742046322040029","DOIUrl":"10.1134/S0742046322040029","url":null,"abstract":"<p>This paper discusses the data of instrumental observations conducted at the Mikhnevo Observatory, at INTERMAGNET observatories, and at the Geophysical Monitoring Center of the Institute of Geosphere Dynamics (IGD), Russian Academy of Sciences (RAS) during the explosive eruption of Hunga Tonga-Hunga Ha’apai Volcano of January 15, 2022. It is shown that the explosion of the volcano produced a series of wave disturbances in the atmosphere, as well as electrical and magnetic variations at large epicentral distances. The atmospheric disturbances were recorded as Lamb waves emitted by a source at the center of the explosion, as well as by a virtual source situated at the antipode. The latter source was formed by convergence and summing of signals propagating on the terrestrial sphere. In addition to primary waves, the recorded phenomena also include secondary and tertiary waves due to multiple passage of the explosion-produced signal around the terrestrial sphere. We evaluated the source energy based on the characteristic frequency in the spectrum of the signal, resulting in the value ~10¹⁸ J, which corresponds to ~200 MT of TNT, when converted to an explosive source. It is shown that a volcanic explosion is accompanied by electrical and magnetic variations both at the time of the explosion and at the time when the recording site receives atmospheric wave disturbances.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 4","pages":"251 - 263"},"PeriodicalIF":0.7,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4562294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Experimental Study and Simulation of Volcanic Structures Using Active Vibroseismic Methods","authors":"B. M. Glinskiy,&nbsp;V. V. Kovalevsky,&nbsp;M. S. Khairetdinov,&nbsp;A. G. Fatyanov,&nbsp;V. N. Martynov,&nbsp;D. A. Karavaev,&nbsp;A. F. Sapetina,&nbsp;A. L. Sobisevich,&nbsp;L. E. Sobisevich,&nbsp;L. P. Braginskaya,&nbsp;A. P. Grigoryuk","doi":"10.1134/S0742046322040030","DOIUrl":"10.1134/S0742046322040030","url":null,"abstract":"<p>This paper is a review of our work, an experimental study and simulation of seismic fields in volcanic structures using vibrators as sources of elastic waves. We review the results of experimental studies of mud volcanoes carried out by the Institute of Computational Mathematics and Mathematical Geophysics (ICM&amp;MG) of the Siberian Branch (SB), Russian Academy of Sciences (RAS); by the Institute of Physics of the Earth (IPE), RAS; and by the Kuban State University in the Taman mud-volcanic province using vibrators. We have carried out mathematical simulation in heterogeneous geophysical media to refine the information on the structure of the object under investigation, as well as on the distinguishing features of the seismic field. We have developed a mathematical approach to deal with the simulation of vibroseismic probing of mud volcanoes with arbitrary geometries incorporating knowledge of deep-seated faults, overlapping layers, and so on. Numerical techniques were used to solve sets of equations in elasticity theory and to develop parallel algorithms, program packages, as well as carrying out numerical experiments in high-performance computational systems. We present results from calculations of the seismic field for the source zone of the Shugo mud volcano. This paper describes 3D and 2D geophysical models developed for this study and the results of simulation for the seismic field of the Karabetova Gora mud volcano and for the Elbrus magmatic volcano. It is shown that the approach developed here using active vibroseismic techniques can be successfully used in practice to refine the seismic field, the deep structure of geophysical models, and to study the effects exerted by the geometry of a magma chamber and by the presence of erupting channels on data acquired by an observation system on the ground surface. These studies prove that vibroseismic sources with high accuracies of periodic excitation can be used to study volcanic structures and to conduct active monitoring of volcanic activity.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 4","pages":"280 - 298"},"PeriodicalIF":0.7,"publicationDate":"2022-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4563517","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}